Dieless sheet forming apparatus with flexible rollers

ABSTRACT

Disclosed is a dieless sheet forming device including: two forming rollers rotatably disposed up and down to correspond with each other and bent to various curvatures; and a plurality of roller adjustment members whose one ends are fixed to each forming roller in such a manner as to be adjusted in length to adjust the curvatures of the forming rollers and the distances between the two forming rollers, wherein the curvatures of the forming rollers and the distances between the forming rollers through which a sheet to be formed is passed are adjusted to change the forming shape of the sheet. According to the present invention, the forming shapes of the sheet can be easily corrected if the desired shape is changed, so that the sheet forming device can be applied for small quantity batch production, does not generate dimples or wrinkles, can form even the edge portions of the sheet, and can form the sheet without having the limitation on the thickness or size of the sheet.

TECHNICAL FIELD

The present invention relates to a dieless sheet forming device, and more particularly, to a dieless sheet forming device that is provided with flexible forming rollers whose curvatures are adjustable, thus being adequate for small quantity batch production.

BACKGROUND ART

So as to form a thick or thin sheet, generally, upper and lower dies 1 corresponding to a desired forming shape of a sheet 3 are made, as shown in FIG. 1, and after the sheet 3 is disposed between the upper and lower dies 1, it is formed by means of a press.

In this case, the conventional sheet forming device using the dies can produce sheets having the same curved shapes as each other in large quantities, but if a desired forming shape is corrected or changed, new dies should be made, so that the die designing cost and the production cost of the final product are all increased, thus being not adequate for small quantity batch production. Besides, even though the desired forming shape is not corrected, additional costs for keeping, maintaining and discarding the dies are needed when the dies are being not used temporarily or permanently.

So as to solve the above-mentioned problems, accordingly, there has been proposed Korean Patent Registration No. 10-1034592 wherein a multi-point sheet forming device includes an upper die 11 a and a lower die 11 b each having a plurality of punches movable up and down independently of each other, as shown in FIG. 2. The conventional multi-point sheet forming device adjusts the heights of the punches formed on the upper die 11 a and the lower die 11 b if a desired forming shape is corrected or changed, thus easily changing the forming shape. However, irregular spaces are formed between the sheet and the forming device due to the radius of curvature of each punch head and the height difference between the punches, which makes it hard to form the curved surface having locally small radius of curvature or edge, and further, since the edges of the sheet are not formed well, they cut to cause the sheet material to be unnecessarily consumed. Moreover, if it is desired to form a thin sheet, not a thick sheet, dimples or local wrinkles occur in accordance with the sizes of the punches.

So as to solve the above-mentioned problems, accordingly, elastic pads 25 made of for example an urethane material are disposed between forming punches 21 a and 21 b and a sheet 23, respectively, as shown in FIG. 3, but the lengths of the punches should be readjusted in accordance with the materials of the elastic pads 25 and desired forming shapes of the sheet 23, which also decreases the operating efficiency of the device and the forming precision of the sheet.

Further, the conventional die forming device and the conventional multi-point forming device using the plurality of punches are restricted in the size of the final forming shape in accordance with the sizes of the dies, and so as to form a large-sized sheet, therefore, the final forming shape is sectionalized and formed. Next, the sectionalized forming shapes are bonded through additional mechanical process and welding to produce the final product, and otherwise, heat is directly applied to the sheet to form the curved surface of the sheet by using residual stress generated by the heat. However, such additional processes increase the forming cost and period of the sheet.

DISCLOSURE Technical Problem

Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a dieless sheet forming device that is simple in configuration to allow a forming shape to be easily corrected even if a desired forming shape is changed, while dimples or wrinkles are being not formed on the formed sheet, thus being adequate for small quantity batch production.

It is another object of the present invention to provide a dieless sheet forming device that can form even the edge portions of a sheet, without having the limitation on the thickness or size of the sheet.

Technical Solution

To accomplish the above-mentioned objects, the present invention proposed a dieless sheet forming device including: two forming rollers rotatably disposed up and down to correspond with each other and bent to various curvatures; and a plurality of roller adjustment members whose one ends are fixed to each forming roller in such a manner as to be adjusted in length to adjust the curvatures of the forming rollers and the distances between the two forming rollers, wherein the curvatures of the forming rollers and the distances between the forming rollers through which a sheet to be formed is passed are adjusted by means of the roller adjustment members to change the forming shape of the sheet.

According to the present invention, that is, the sheet is formed between the two forming rollers disposed up and down, which makes the configuration of the device simple and allows the sheet to be formed without having any limitation on the lengthwise size thereof. Further, the curvatures of the forming rollers and the distance between the forming rollers are adjusted by means of the roller adjustment members, which make the forming shape easily corrected, so that the device of the invention is adequate for small quantity batch production.

In accordance with a preferred embodiment, each roller adjustment member includes an external member having an internal screw thread and an internal member having an external screw thread and is adjusted in length in accordance with the screw-coupled length between the external member and the internal member.

According to the present invention, like this, the curvatures of the forming rollers are differently adjusted by means of the length adjustment of the roller adjustment members, which produces sheets having a single curvature, a double curvature, a multi curvature, a twisted shape and the like.

In accordance with a preferred embodiment, the external member is fixed to one of two forming rollers, and the internal member is connected to the motor, so that the length of each roller adjustment member can be adjusted through the rotation of the motor. Each roller adjustment member may be connected to a separate motor, and otherwise, the plurality of roller adjustment members may be adjusted in lengths through the movement of a single motor or a plurality of motors. Like this, the lengths of the roller adjustment members can be easily adjusted through the motors.

In accordance with a preferred embodiment, the end of the external member fixed to one of two forming rollers is rotatably provided with a roller guide, which has a recess having a shape of major arc (an arc bigger than a semicircle), into which the forming roller is fittedly inserted. That is, while each forming roller is being fittedly mounted into the rotatable recesses of the roller guides thereof, the roller adjustment members are adjusted in lengths to easily change the various curvatures of the forming roller.

According to the present invention, the sheet to be formed is inserted between the two forming rollers and pulled so as to be passed through between the forming rollers, thus completing the forming operation of the sheet. One of the forming rollers may be connected and rotated at both ends thereof to roller rotation motors, and otherwise, both of the forming rollers may be drove by the roller rotation motors. In this case, the sheet engaged with the forming rollers is pushed and formed through the rotation of the roller rotation motors.

Each forming roller is made of steel having high modulus of elasticity. Solid bar-type rollers can be treated through heat treatment allowing an adequate elastic behavior during forming procedure. Alternatively, each forming roller is wound by a plurality of steel wires, and at this time, desirably, the steel wire wound on the outer peripheral surface of each forming roller becomes flat on an outside surface contacted with the sheet, through grinding. Otherwise, the steel wire wound on the outer peripheral surface of each forming roller has an oval section to allow the outside surface contacted with the sheet to be flat. Like this, the sheet is formed along the continuously curved surfaces of the forming rollers having flat outer peripheral surfaces, thus providing the sheet having a smooth formed surface on which no local dimples or wrinkles exist.

Advantageous Effects

The dieless sheet forming device according to the present invention can adjust the shapes of the upper and lower forming rollers and the distance between them to form a sheet, and can be accordingly simple in configuration and relatively small in installation area, thus greatly reducing the die production cost, the die storing cost and the die maintenance cost.

The curvatures of the forming rollers and the distances between them can be adjusted by means of the roller adjustment members, thus performing various changes in the forming shapes, so that the device can be adequate for small quantity batch production and can form a large-sized sheet, without having any limitation on the length of the sheet, thus needing no additional mechanical process.

The sheet can be formed along the continuous curved surfaces of the forming rollers, without having any punches, so that even the edges of the sheet can be formed and no dimples or wrinkles is formed even on a thin sheet.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view showing one conventional die sheet forming device.

FIG. 2 is a schematic view showing another conventional multi-point sheet forming device.

FIG. 3 is a schematic view showing still another conventional multi-point sheet forming device having elastic pads.

FIG. 4 is a schematic perspective view showing a dieless sheet forming device according to the present invention.

FIG. 5 is a perspective view showing a roller adjustment member used in the dieless sheet forming device according to the present invention.

FIG. 6 is a partial sectional view showing an example of the roller adjustment member of FIG. 5 coupled to a motor.

FIG. 7 is a sectional view showing another example of the roller adjustment member of FIG. 5 coupled to a motor.

FIG. 8 is a side view showing one example of a forming roller used in the dieless sheet forming device according to the present invention.

FIG. 9 is a side view showing another example of a forming roller used in the dieless sheet forming device according to the present invention.

FIG. 10 is a schematic perspective view showing one example of the sheet forming between two forming rollers.

FIG. 11 is a schematic perspective view showing another example of the sheet forming between two forming rollers.

FIG. 12 is a sectional view showing the arrangement of the upper and lower forming rollers when a convex type sheet is formed through the dieless sheet forming device according to the present invention.

FIG. 13 is a perspective view showing the forming shape of the sheet through the arrangement of the upper and lower forming rollers of FIG. 12.

FIG. 14 is a sectional view showing the arrangement of the upper and lower forming rollers when a saddle type sheet is formed through the dieless sheet forming device according to the present invention.

FIG. 15 is a perspective view showing the forming shape of the sheet through the arrangement of the upper and lower forming rollers of FIG. 14.

FIG. 16 is a sectional view showing the arrangement of the upper and lower forming rollers when a twisted type sheet is formed through the dieless sheet forming device according to the present invention.

FIG. 17 is a perspective view showing the forming shape of the sheet through the arrangement of the upper and lower forming rollers of FIG. 16.

MODE FOR INVENTION

Hereinafter, an explanation on a dieless sheet forming device according to a preferred embodiment of the present invention will be in detail given with reference to the attached drawings.

FIG. 4 is a schematic perspective view showing a dieless sheet forming device according to the present invention. As shown, a dieless sheet forming device 100 according to the present invention has two forming rollers 101 a and 101 b horizontally disposed up and down to correspond with each other. The forming rollers 101 a and 101 b can be flexibly bent to various curvatures, respectively.

Each of the forming rollers 101 a and 101 b is equipped with a plurality of roller adjustment members 103 so as to adjust the curvature. FIG. 5 shows an example of the roller adjustment member 103, and FIG. 6 is a partial sectional view showing the roller adjustment member 103 in detail. The roller adjustment member 103 includes an external member 105 having an internal screw thread and an internal member 107 having an external screw thread. The internal member 107 is fittedly screw-coupled to the external member 105, and the roller adjustment member 103 is adjusted in length in accordance with the screw-coupled length between the external member 105 and the internal member 107.

So as to easily adjust the length of the roller adjustment member 103, as shown in FIG. 6, the roller adjustment member 103 is connected to a motor. That is, the external member 105 is fixed to the forming roller, and the internal member 107 is connected to the motor, so that as the coupled depths of the internal member 107 to the external member 105 are varied through the rotation of the motor, the whole length of the roller adjustment member 103 can be adjusted. A separate motor may be connected to each roller adjustment member 103, but as shown in FIG. 7, the plurality of roller adjustment members 103 may be adjusted in lengths through the movement of a single motor or a plurality of motors.

The respective internal members 107 are rotated by means of the single motor or the plurality of motors, thus adjusting the lengths of the roller adjustment members 103, and accordingly, the shape of the forming roller connected to one ends of the external members 105 and the distance between the upper and lower forming rollers 101 a and 101 b can be adjusted.

Returning to FIGS. 5 and 6, the roller adjustment member 103 has a roller guide 109 disposed rotatably at the end thereof fixed to the forming roller 101 a or 101 b, that is, at the bottom end of the external member 105. The roller guide 109 has a recess 109 a having a shape of major arc, into which the forming roller 101 a or 101 b is fittedly inserted. As the plurality of roller adjustment members 103 is vertically arranged with respect to the horizontally arranged two forming rollers 101 a and 101 b, the rotatable roller guides 109 to which the forming rollers 101 a and 101 b are fitted are adapted to allow the forming rollers 101 a and 101 b to be naturally bent when the curvatures of the forming rollers 101 a and 101 b are adjusted through the length adjustment of the roller adjustment members 103.

FIGS. 8 and 9 show examples of the forming roller. As shown, the forming roller 101 a is wound by a plurality of steel wires to a plurality of layers. The steel wire wound on the outermost peripheral surface of the forming roller 101 a is desirably flat, on an outside surface 111 contacted with a sheet, through grinding. As the outside surface 111 of the forming roller 101 a contacted with the sheet is flat, occurrences of local dimples or wrinkling can be prevented. Alternatively, the steel wire wound on the outermost peripheral surface of the forming roller 101 a has an oval section to allow the outside surface 111 contacted with the sheet to be flat. In the drawings, one forming roller 101 a has been described, but the other forming roller 101 b has the same configuration as the forming roller 101 a.

Further, as shown in FIG. 4, the forming rollers 101 a and 101 b may be connected at both ends thereof to roller rotation motors 113, thus being automatically rotated. In this case, as shown in FIG. 10, the sheet 102 is fittedly disposed between the forming rollers 101 a and 101 b and thus pushed and formed through the rotation of the forming rollers 101 a and 101 b. At this time, the forming shapes of the sheet 102 are determined upon the shapes of the forming rollers 101 a and 101 b and the distance between them, and as mentioned above, the shapes of the forming rollers 101 a and 101 b and the distance between them are adjusted by means of the roller adjustment members 103 in accordance with desired forming shapes of the sheet 102. Alternatively, the roller rotation motors 113 may be connected to any one of the forming rollers 101 a and 101 b, thus transmitting the driving force, and otherwise, no roller rotation motors 113 may be provided. In case of the non-existence of the roller rotation motors 113, as shown in FIG. 11, the sheet 102 is inserted between the forming rollers 101 a and 101 b and pulled and formed from the opposite side to the inserted portion. In the same manner as above, the forming shapes of the sheet 102 are determined upon the shapes of the forming rollers 101 a and 101 b and the distance between them, and the shapes of the forming rollers 101 a and 101 b and the distance between them are adjusted by means of the roller adjustment members 103.

Like this, since the sheet 102 is formed through the adjustment of the shapes of the forming rollers 101 a and 101 b and the distance between them, the forming shapes of the sheet 102 can be simply corrected in accordance with the changes of the desired forming shapes of the sheet 102. Further, the forming rollers 101 a and 101 b providing the continuous forming surfaces are rotated while interposing the sheet 102 therebetween, thus forming the sheet 102, so that no dimples or wrinkles exist.

Hereinafter, examples of forming the sheet through the dieless sheet forming device according to the present invention will be in detail explained.

In the dieless sheet forming device 100 according to the present invention, the forming shapes of the sheet 102 are determined upon the curvatures of the two forming rollers 101 a and 101 b corresponding up and down with each other and the distance between them. That is, a length of the formed sheet 102 becomes longer as the gap between the forming rollers 101 a and 101 b is narrower, and contrarily, a length of the formed sheet 102 is shorter as the gap between the forming rollers 101 a and 101 b is wider. Under the above principle, the curved surface of the sheet 102 is formed.

For example, as shown in FIG. 12, if the gap between the forming rollers 101 a and 101 b is narrow in the middle portion c of the forming rollers 101 a and 101 and wide in the edge portions a and e thereof to provide a distance (a=e)>(b=d)>c, a length of the formed sheet 102 becomes long in the middle portion c′ of the formed sheet 102 and short in the edge portions a′ and e′ thereof, as shown in FIG. 13, thus providing a length c′>(b′=d′)>(a′=e′) and accordingly forming the convex type sheet 102.

Further, as shown in FIG. 14, if the gap between the forming rollers 101 a and 101 b is wide in the middle portion c of the forming rollers 101 a and 101 and narrow in the edge portions a and e thereof to provide a distance c>(b=d)>(a=e), a length of the formed sheet 102 becomes short in the middle portion c′ of the formed sheet 102 and long in the edge portions a′ and e′ thereof, as shown in FIG. 15, thus providing a length (a′=e′)>(b′=d′)>c′ and accordingly forming the saddle type sheet 102.

Furthermore, as shown in FIG. 16, if the gap between the forming rollers 101 a and 101 b is gradually wider in one direction thereof to provide a distance e>d>c>b>a, a length of the formed sheet 102 becomes gradually longer in the order of a′>b′>c′>d′>e′, thus forming the twisted type sheet 102.

The curvatures and distances of the forming rollers 101 a and 101 are adjusted to various sheets by means of the length adjustment of the roller adjustment members 103, and accordingly, the sheet 102 can be formed to various shapes. Therefore, the sheet forming device according to the present invention can be applied for small quantity batch production, can form even the edge portions of the sheet, and can form the sheet without having the limitation on the length of the sheet.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention. 

1. A dieless sheet forming device comprising: two forming rollers rotatably disposed up and down to correspond with each other and bent to various curvatures; and a plurality of roller adjustment members whose one ends are fixed to each forming roller in such a manner as to be adjusted in length to adjust the curvatures of the forming rollers and the distances between the two forming rollers, wherein the curvatures of the forming rollers and the distances between the forming rollers through which a sheet to be formed is passed are adjusted by means of the roller adjustment members to change the forming shape of the sheet.
 2. The dieless sheet forming device according to claim 1, wherein each roller adjustment member comprises an external member having an internal screw thread and an internal member having an external screw thread and is adjusted in length in accordance with the screw-coupled length between the external member and the internal member.
 3. The dieless sheet forming device according to claim 2, wherein the external member is fixed to one of the forming rollers, and the internal member is connected to the motor, so that the length of each roller adjustment member is adjusted through the rotation of the motor.
 4. The dieless sheet forming device according to claim 2, wherein the external member is fixed to one of the forming rollers, and each roller adjustment member has a roller guide disposed rotatably at the end of the external member fixed to the forming roller, the roller guide having a recess of a major arc shape, into which the forming roller is fittedly inserted.
 5. The dieless sheet forming device according to claim 1, wherein the sheet to be formed is inserted between the two forming rollers and pulled so as to be passed through between the forming rollers, thus completing the forming of the sheet.
 6. The dieless sheet forming device according to claim 1, wherein one or both forming rollers are connected at both ends thereof to roller rotation motors, so that the sheet engaged with the forming rollers is pushed and formed through the rotation of the roller rotation motors.
 7. The dieless sheet forming device according to claim 1, wherein each forming roller is wound by steel wires on the outer peripheral surface.
 8. The dieless sheet forming device according to claim 7, wherein the steel wire wound on an outmost surface of each forming roller contacted with the sheet becomes flat through grinding.
 9. The dieless sheet forming device according to claim 7, wherein the steel wire wound on an outmost surface of each forming roller contacted with the sheet has an oval section. 